Sealing cover with pressure compensation channel

ABSTRACT

A petrol tank cap has a tensional diaphragm and seatings set so as to relieve abnormal under- and over-pressures in the tank. To ensure that only a small quantity of liquid can escape with the gas, the cap includes a partition with a narrow V-shaped groove, the dimensions of which are such as to allow passage of gas, but to severely restrict escape of liquid.

United States Patent Gerdes June 24, 1975 [54] SEALING COVER WITH PRESSURE l,380,045 5/192; sDlplezal 220/44 A 2,l 17,369 5/193 aw COMPENSATION CHANNEL M 8 2/1940 Deeley VVV n [75] Inventor: Theo Gerdes, Langenfeld, 2,440,462 4/1948 Cooper Rhineland, Germany 3,233,727 2/1966 Wilson 3,406,862 lO/l968 Donaldson 220/44 C [731 Asslgnee: Fabnk 3,696,958 10/1972 Lee 220/44 c Kraftt'ahrzeugteile, Langenfeld, Rhineland, Germany [22] Filed; Sept 13, I973 Primary Examiner-John Petrakes Appl. No.: 397,093

Foreign Application Priority Data Sept. 29, 1972 Germany 2248033 References Cited UNITED STATES PATENTS Hcnnessey 220/44 R Attorney, Agent, or Firm-Michael S. Striker [57] ABSTRACT A petrol tank cap has a tensional diaphragm and seatings set so as to relieve abnormal underand overpressures in the tank. To ensure that only a small quantity of liquid can escape with the gas, the cap includes a partition with a narrow V-shaped groove, the dimensions of which are such as to allow passage of gas, but to severely restrict escape of liquid.

5 Claims, 2 Drawing Figures Ill 1 SEALING COVER WITH PRESSURE COMPENSATION CHANNEL The present invention concerns a pressure compensation channel formed in a partition in the circumferential edge of a sealing cover and, more particularly, in a channel extending transversely across a projecting centre dome of a partition member, in co-operation with a valve-like acting control diaphragm which is held in contact under tension against the circumferential edge of the centre dome.

The problem of designing such sealing covers to include automatic compensation of over-pressures or under-pressures within a container or pipe socket may be seen in that internal gas pressure compensation must be compensated at all times, i.e., automatic evacuation of gas must be possible to balance an internal overpressure, whilst a leakage of for example internally agitated liquid or a flood of liquid due to the action of pressure or temperature, must be prevented. Precautions must be taken to ensure that liquid cannot flow through this communicating passage, which must release gas pressure only.

It is an object of the present invention to provide a sealing cover having a groove-like pressure compensation channel for achieving automatic over-pressure or under-pressure compensation of a closed container or pipe socket.

In accordance with the present invention there is provided a sealing cover for a container or pipe socket closure with automatically acting compensation of internal overand under-pressures, comprising a partition clamped at the circumference of the cover, with ventilation holes and groove-like channels serving for excess gas pressure compensation, wherein a partition in the cover is provided with a groove-like gas pressure compensation channel having such an entry dimension and depth as to restrict the flow of liquid therethrough.

The present invention will now be described with reference to an embodiment applied to scaling covers having a valve-like control diaphragm held in close contact with the centre dome of a partition inserted in the cover, such as are used for the fuel tanks of vehicles.

In the accompanying drawings:

FIG. I shows a sealing cover in a central crosssection.

FIG. 2 shows a plan view of the centre dome of the partition of the cover.

FIG. 1 shows a conventional bayonet lock sealing cover, having an upper cover member 1 a contact finger grip rib I pressed out upwardly, and a rim or lip 1" drawn down to form an outer edge. This rim 1" encloses a lower pot-shaped spring housing 2, inserted by its upper flanged edge 2' and uniformly compressed by the upper cover member 1. Mounted in the spring housing 2 is a bayonet bridge member 3 with a compensation spring 4 supported against the base 2 of the potshaped housing, the bayonet pins 3' extending through cut-outs 2" in the pot-shaped wall of the spring housing 2. By turning the cover a relatively to mounting edges of a container or pipe socket (not shown), the cover is resiliently tightened with its seal 8 against the edge of the container opening,

There is a partition 5 with a circular dome 5 projecting inwardly in the centre, and a control diaphragm 6 in sealing contact with the circumferential edge of this dome 5'. The diaphragm 6 has a large central hole 6',

and is firmly held between the parts 1 and 2 of the cover. A sealing washer 7 is located on the flanged edge 2' of the lower cover 2.

Transversely across the centre of the dome 5' and passing across the centre of the hole 6' of the control diaphragm 6 there is a groove-like channel 5" the liquid-repelling inlet width of which is small compared with the diameter 6' of the hole in the diaphragm, and extending upwardly to a distance which is a multiple of its inlet width. The channel is formed in a projecting rib 5" and has a lightly restrictive action on liquid flow therethrough.

Experiments have shown that this type of very deep and narrow channel formed in the dome 5' with a very narrow input width are effective to preclude the passage of liquid, even with a comparatively high internal pressure rise, whilst allowing excess gas pressure to be relieved.

FIG. I also shows that the control diaphragm 6 is mounted to rise slightly from its outer clamping point in the edge of the cover A towards the centre as a sealing edge in a tensioned form relatively to the circumference of the dome 5' in such manner that it extends continuously towards its centre hole 6 at the most acute angle possible, relatively to the horizontal surface of the dome 5. The centre hole 6 is so dimensioned that the remaining edge surface of the control diaphragm projects only slightly free from the sealing edge of the dome 5' as far as the edge 6' of the hole. This prevents sprayed liquid or floods of liquid under comparatively high pressures from penetrating into the acute and short angular space between the dome 5' and control diaphragm 6/6, whereby the control diaphragm 6 might be drawn from its sealing edge seat on the dome 5'.

Gas pressure compensation is effected in the case of an internal underpressure by an automatic valve-like raising of the control diaphragm 6 inwardly from the sealing edge of the centre dome 5', so that air intake takes place automatically through channels 2" from below the edge I" of the cover and cut-outs 5" in the outer edge of the partition 5, thence inwardly by way of ventilation holes 5" in the partition between the edge of the cover and the centre dome 5'. If, however, an internal overpressure occurs, gas pressure relief is effected by way of the grooved channels 5" on both sides of the dome 5', as shown in FIG. 2, for this purpose. External pressure compensation and ventilation are then effected automatically from under the edge I" of the cover in the reverse direction by way of cut-outs 5" in the circumference and grooves 2" in the externally drawn down flanged edge 2'.

I claim:

1. In a sealing cover for closing a container adapted to contain a mixture of liquids and gases, particularly fuel storage tanks or the like, a combination comprising a housing defining an enclosed space; wall means provided within said housing and subdividing said enclosed space into a first compartment adapted to communicate with the ambient atmosphere and a second compartment adapted to communicate with the container, said wall means being formed with a centrally located projection extending into said second compartment and with an outer portion having a plurality of apertures extending therethrough; a flexible pretensioned diaphragm provided within said housing and having an outer marginal portion overlying said outer portion of said wall means defining an annular space therewith which communicates with said apertures and an inner marginal portion overlying said centrally located projection and normally sealingly engaging the latter and bounding a center opening of said diaphragm; a groove-shaped channel formed in said projection and having an inlet communicating with said second compartment by means of said central opening in said diaphragm and dimensioned to allow entry of gas but to substantially restrict the entry of liquid into said channel. said channel having at least one outlet communicating with said annular space, whereby a force is exerted on said inner marginal portion of said diaphragm disengaging the latter from said projection when the pressure of the ambient atmosphere exceeds the pressure in said container so that the atmosphere may be admitted via said second compartment into the container, and an oppositely directed force is exerted on said inner marginal portion to urge the latter against said projection when the pressure in said container exceeds the pressure of the atmosphere so that the gaseous component of said mixture may enter said grooveshaped channel for discharge to the ambient atmosphere, whereby the pressure in said container may be automatically equalized.

2. In a sealing cover as defined in claim 1, wherein said projection is circular, and wherein said opening of said inner marginal portionof said diaphragm is circular and has an area which is larger than the intake area of said inlet of said groove-shaped channel.

3. In a sealing cover as defined in claim I, whereiin said outer portion of said wall means has edges which are clamped to said housing, said wall means extending inwardly from said edges towards said projection.

4. In a sealing cover as defined in claim 1, wherein said groove-shaped channel is of V-shaped crosssection.

5. In a sealing cover as defined in claim I, wherein the depth of said groove-shaped channel is greater than its width. 

1. In a sealing cover for closing a container adapted to contain a mixture of liquids and gases, particularly fuel storage tanks or the like, a combination comprising a housing defining an enclosed space; wall means provided within said housing and subdividing said enclosed space into a first compartment adapted to communicate with the ambient atmosphere and a second compartment adapted to communicate with the container, said wall means being formed with a centrally located projection extending into said second compartment and with an outer portion having a plurality of apertures extending therethrough; a flexible pretensioned diaphragm provided within said housing and having an outer marginal portion overlying said outer portion of said wall means defining an annular space therewith which communicates with said apertures and an inner margInal portion overlying said centrally located projection and normally sealingly engaging the latter and bounding a center opening of said diaphragm; a grooveshaped channel formed in said projection and having an inlet communicating with said second compartment by means of said central opening in said diaphragm and dimensioned to allow entry of gas but to substantially restrict the entry of liquid into said channel, said channel having at least one outlet communicating with said annular space, whereby a force is exerted on said inner marginal portion of said diaphragm disengaging the latter from said projection when the pressure of the ambient atmosphere exceeds the pressure in said container so that the atmosphere may be admitted via said second compartment into the container, and an oppositely directed force is exerted on said inner marginal portion to urge the latter against said projection when the pressure in said container exceeds the pressure of the atmosphere so that the gaseous component of said mixture may enter said groove-shaped channel for discharge to the ambient atmosphere, whereby the pressure in said container may be automatically equalized.
 2. In a sealing cover as defined in claim 1, wherein said projection is circular, and wherein said opening of said inner marginal portion of said diaphragm is circular and has an area which is larger than the intake area of said inlet of said groove-shaped channel.
 3. In a sealing cover as defined in claim 1, whereiin said outer portion of said wall means has edges which are clamped to said housing, said wall means extending inwardly from said edges towards said projection.
 4. In a sealing cover as defined in claim 1, wherein said groove-shaped channel is of V-shaped cross-section.
 5. In a sealing cover as defined in claim 1, wherein the depth of said groove-shaped channel is greater than its width. 